Battery packs for use as power sources in carrying portable personal computers (hereinafter, referred to as portable PCs) have a battery charge displaying function and a battery protecting function. Power management systems such as a smart battery system are constituted in which data including the battery voltage and the battery charge are output to PC bodies through communication buses (such as SMBus) and the PC bodies control the battery packs. In offices etc., portable PCs loaded with such battery packs are connected to the LAN so that they can acquire and update necessary information from a management computer for performing maintenance.
Since the information on the battery packs is transmitted to the PC bodies through the communication buses, the management computer can acquire the information on the battery packs from the portable PCs. The information on the battery packs includes data such as the dates of manufacture, serial numbers, battery capacities, and battery voltages. From the data acquired, the management computer identifies replacement times, available models for capacity enhancement, etc.
The information on the battery packs is, however, in a format solely for communication between the battery packs and the portable PCs. Thus, it must be converted into data formats recognizable on the network by the portable PCs, and the management computer cannot acquire the information on the battery packs unless the portable PCs are in operation. In addition, the information acquisition intended for maintenance and the like is performed at nighttime so as not to interfere with any business operation that uses computers including the portable PCs. At nighttime, the portable PCs are often powered OFF, which precludes the information acquisition.
It is an object of the present invention to provide a battery pack which has a unique address and network communication means so that the battery pack can establish connection with the network by itself.